替换ereg_replace [重复]

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How can I convert ereg expressions to preg in PHP?

I have upgraded php and now im getting the ereg_replace deprecated errors.

I have done some searching round web and found that I can use preg instead but not sure how to change this code correctly

$scriptName = ereg_replace(
    "^".$_SERVER["DOCUMENT_ROOT"], "", 
    $_SERVER["SCRIPT_FILENAME"]
);

Just adding delimiters won't work when special characters are included in $_SERVER["DOCUMENT_ROOT"]'s value. You need to escape them as follows:

$scriptName = preg_replace(
  "/^".preg_quote($_SERVER["DOCUMENT_ROOT"],"/")."/",
  "", 
  $_SERVER["SCRIPT_FILENAME"]
);

Replace the e with a p.

Add a delimiter to the beginning and end of that first argument. Traditionally, people use slashes (/), but I like to use ~ as there is less chance of actually using that character in the regular expression.